Participants in this research study have had a positive islet cell antibody test. The purpose of this study is to look at immune system and pancreas function because participants are at an increased risk of developing Type 1 Insulin Dependent Diabetes Mellitus (IDDM). In the initial screening protocol, we have identified a substance in participants' blood called islet cell autoantibodies (ICA). ICA may be found in the blood of some individuals who may develop diabetes years before they develop symptoms, although a negative ICA test does not mean an individual cannot develop diabetes. To help understand the importance of the ICA, we will obtain blood samples from participants to see if there are other markers which may predict development of IDDM. We would also like to perform tests to see if participants' glucose levels go up too high or if insulin levels are too low. At the same time, we would like to assess the status of participants' immune systems as they relate to the potential development of IDDM..